Manufacture of sulfuric acid and sodium sulfate.



- cessful because it fuses under heat, and prac- 'the value of part of that of the sulfuric acid from which it 30 UNIT-ED srnrns PATENT orrron ULRICH FRIEDRICH BENKER, or oL'ioHr, FRANCE.

MANUFACTURE OF SULFURIC To all whom it may concern:

Be it known that I, ULnioH FRIEDRICH BENKER, a citizen of the Republic ofSwitzerland, residing at 120 Rue Martre, Clichy, Seine, in the Republic of France, chemist, have in vented certain new and useful Improve ments in the 'Manufacture of Sulfuric Acid and Sodium Sulfate, of which the following is a specification. I

This invention has for its object a process of (inaking sulfuric acid and neutral sulfate of so a.

It is known that the bi-sulfate of soda obtainediin such large quantities in the manufactureof nitricacid is a product for whichno rational use has hitherto been found.

In certain cases, bi-sulfate of soda is used for the preparation of neutral sulfate of soda by mixing it withsea salt, this mixture being heated in special furnaces whereby hydrochloric acid is obtained on the one hand and neutral sulfate on the' other. 7 This process can only be utilized when there is a-use for the hydrochloric acid.

Another method consists in heating the bi-sulfate with carbon and in this case thesulfuric acid is converted into sulfurous acid, which only represents a small is obtained.

The attempts made to decomposethe bisulfate by heat alone, have proved unsuctically speaking, no. apparatus will resist the action of fused bi-sulfate; a ain if the bi-sulfate be heated to a white-red, 8 to 10 only of the sulfuric acid is liberated.

The inventor has found that by intimately mixingv the bi-sulfate of soda with an appropriate quantity of, silica (fine sand) or of Specification of Letters Patent. I Application filed March a, 1907.

', placed my hand.

non: AND sonnmr SULFATE,

Patented Sept. 22, 1908. s riaino'. sconce.

finely pulverized silicates,

corresponding to the sulfuric acid of the neu" liberated very readily at tral su fate becomes .red. heat. 7 i The mixture of bi-sulfate and of the inert to a red heat (500 to substance is heated 600 (1). As the'anhydrous sulfates of soda and .potash onlymelt' to 900 C.)theya1"e notfused in the process. The inert substance has no chemical action on the bi-sulfate but absorbs it mechanically as fast as the bi-sulfate melts so'that the mixture remains in a dry at a white'heat (800 and sand-like condition.

or again, with any substance unattacked by the bi-sulfate, such as the anhydrous sulfates The proportions between the bi-sulfate of soda and the inert substances will vary according to the nature of these latterbodies.

When silica isiemployed, it is preferably taken in substantially equalproportions to the bi-sulfate. The sulfuric acid which is liberated. may be collected in-a concentrated state in appropriate apparatus.

I claim: a v

A process for making free sulfuric acid and neutral sulfate of sodaby the decomposition of bisulfate of soda, consisting. in heating a mixture of bi-sulfate of soda and of silica in substantially equal proportions, thus pre' venting the fusion of the bi-sulfate.

In testimony of which I have hereunto ULRICH FRlEDRICH BENKER. 

